This invention relates generally to methods and apparatus for facilitating computed tomographic (CT) image assessment, and more particularly to methods and apparatus for enhancing functional data on CT images.
In at least some computed tomography (CT) imaging system configurations, an x-ray source projects a fan-shaped beam which is collimated to lie within an X-Y plane of a Cartesian coordinate system and generally referred to as the xe2x80x9cimaging planexe2x80x9d. The x-ray beam passes through the object being imaged, such as a patient. The beam, after being attenuated by the object, impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array is dependent upon the attenuation of the x-ray beam by the object. Each detector element of the array produces a separate electrical signal that is a measurement of the beam attenuation at the detector location. The attenuation measurements from all the detectors are acquired separately to produce a transmission profile.
In known third generation CT systems, the x-ray source and the detector array are rotated with a gantry within the imaging plane and around the object to be imaged so that the angle at which the x-ray beam intersects the object constantly changes. X-ray sources typically include x-ray tubes, which emit the x-ray beam at a focal spot. X-ray detectors typically include a collimator for collimating x-ray beams received at the detector, a scintillator adjacent the collimator, and photodetectors adjacent the scintillator.
Computed tomography (CT) is an anatomical imaging modality, but recently there have been advances that give some functional imaging capabilities to CT. For example, one known image software package for CT perfusion provides facilities for a user to process dynamic image data and to generate functional information and images that include functional image data relating to perfusion. The software uses changes in image intensity as a function of time to generate the information and the images. However, CT has classically been a grayscale-only modality, and it is difficult to assess differences in data on such images.
There exist known embodiments of other imaging modalities, such as nuclear medicine and positron emission tomography (PET), that regularly utilize functional maps to show differences. Color is often utilized with these modalities to give better discrimination than grayscale maps in the assessment of the displayed data.
CT Perfusion is a functional imaging software and is similar to perfusion packages in nuclear medicine or MR but is a unique use for CT.
It would therefore be desirable to provide methods and apparatus for computed tomographic imaging that facilitated the assessment of images, and differences between images, especially for functional image data, and more particularly for perfusion-related imaging data.
One embodiment of the present invention is therefore a method for facilitating the analysis of computed tomographic (CT) images. The method includes steps of: acquiring attenuation data of a patient using a CT imaging system; reconstructing images of the patient using the acquired attenuation data; mapping intensity data from at least one reconstructed image into a color image using a color mapping indicative of physiological thresholds; and displaying the color image.
Embodiments of the present invention facilitate the assessment of images and differences between images for functional image data and for perfusion-related imaging data.